The menace of diabetes is all pervading across the globe and with the growing rate of diabetic patients. India is going to be the capital of diabetes soon. However, an early detection of diabetes can lower the potential dangers of the killer disease. Blood sugar monitoring (Fasting plasma glucose and Oral glucose tolerance test) is a time-tested reliable method of diabetes detection. However, the process is expensive, and on the top, an invasive one. To get around the problem, different non-invasive and minimally-invasive techniques like IR spectroscopy, optical rotation of polarized light, radio wave impedance, analysis of tear, analysis of fluid extracted from skin and biosensors to monitor diabetes from a drop of blood have been studied. So far, no non-invasive household gadget is available in the market for monitoring diabetes.
Many different non-invasive and minimally invasive techniques (as mentioned above) so far have been attempted to monitor diabetes [1,2]. Incidentally, it has been known for a long time that the acetone concentration in human breath increases in diabetic patients. it has been given that acetone concentration of <0.9 ppm in breath can be taken as normal for a healthy individual and concentration >1.7 ppm indicates diabetes [1,2]. There is also a good correlation between breath acetone concentration and blood sugar level [3]. Most studies on breath acetone measurements have been performed on highly sophisticated instruments like GC-MS, SFFT-MS and cavity ring down spectroscopy [4,5]. Other methods are C-13 labelled pyruvic acid-based measurements (U.S. Pat. No. 7,118,919 B2, U.S. Pat. No. RE38,575 E and WO1999/56790 A2), ion mobility spectrophotometer (U.S. Pat. No. 6,794,645 B2), microplasma in combination with spectrometer (U.S. Pat. No. 7,417,730 B2, US2004/137637 A1) [6,7] etc. Incidentally, metal oxide semiconductors like SnO2, WO3, ZnO and TiO2 have recently been studied for low concentration acetone detection (WO2011/068976 A1) [7-20] as semiconductor sensors are inexpensive, rugged and handy. For example, Ag nanoparticles-modified TiO2 sensor has 10 ppm detection limit of acetone vapour [8] and ZnO nanowires and dumbbell-like ZnO microcrystals have acetone detection limits down to 5 ppm and 1 ppm, respectively [14,15]. The sub-ppm acetone sensitivity using undoped or doped γ-Fe2O3 sensor at moderate working temperature of 150° C. has been reported earlier [1,9]. A 10 mol % SiO2 doped ε-WO3 composition showed an adequate sensitivity in low concentrations (100 ppb to 900 ppb) of acetone vapour at a working temperature of 400° C. [20].
The drawbacks of the so far studied metal oxide semiconductor sensors are:                i) The sensitivity for detecting the acetone concentration in the low ppm or sub-ppm range is not high enough for making devices.        ii) The prior art reported sensors are moisture sensitive and hence are not selective to acetone in presence of high moisture (normally present in breath).        
Considering the drawbacks of the prior art sensors, the present inventors have developed the composition which overcome such drawbacks of the prior art sensors. The sensors fabricated using claimed composition shows appreciable sensitivity at ˜1 ppm acetone concentration and high selectivity, and are at the same time insensitive to high amount of moisture present in breath.